The purpose of this contract is to conduct a study to determine nationally, as well as in select metropolitan areas, the prevalence and impact of alcohol and other drug abuse and dependence in short-term general hospitals. The major objectives of this project are: * Determine the national prevalence rates of alcohol abuse and alcoholism and polysubstance abuse primary of principal (first listed) and secondary (all other listed) diagnoses in hospital. * Determine the national prevalence rates of alcohol abuse and alcoholism and polysubstance abuse in hospitals based on each of the following types/sources of data: diagnostic survey questionnaire, medical record comorbidity data, and medical record blood chemistry data. * Determine the aforementioned prevalence levels by selected hospital and patient characteristics, e.g., hospital location, type of medical of surgical service, selected patient characteristics, and non-alcohol diagnoses. * Determine the relationships among the aforementioned prevalence estimates. In addition, assess the degree of validity of each of the prevalence estimates. * Develop national alcohol and other drug hospital prevalence estimation formulae based on each of the aforementioned types/sources of data alone and in combination. * Determine the impact of alcohol and other drug abuse and dependency on hospitals resource utilization, charges, and costs.